This invention comprises a retainer clip adapted to hold a first object in position inside a second object, such as a tube or conduit, which has a circular cross-section. More specifically, the invention relates to a heatsink/retainer member operable to support electronic circuit boards within the interior of a toroidal coupled measurements-while-drilling (MWD) telemetry tool.
In the oil industry, the incentives for making downhole measurements during drilling operations are substantial. In this connection, downhole measurements while drilling will allow safer, more efficient, and more economic drilling of both exploration and production wells.
Continuous monitoring of downhole conditions will allow immediate response to potential well control problems. This will allow better mud programs and more accurate selection of casing seats, possibly eliminating the need for an intermediate casing string, or a liner. It also will eliminate costly drilling interruptions while circulating to look for hydrocarbon shows at drilling breaks, or while logs are run to try to predict abnormal pressure zones.
Drilling will be faster and cheaper as a result of real time measurement of parameters such as bit weight, torque, wear and bearing condition. Faster penetration rate, better trip planning, reduced equipment failures, delays for directional surveys, and elimination of a need to interrupt drilling for abnormal pressure detection, could lead to a 5 to 15% improvement in overall drilling rate.
In addition, downhole measurements while drilling may reduce costs for consumables, such as drilling fluids and bits, and may even help avoid setting pipe too early. Were MWD to allow elimination of a single string of casing, further savings could be achieved since smaller holes could be drilled to reach the objective horizon. Since the time for drilling a well could be substantially reduced, more wells per year could be drilled with available rigs. The savings described would be free capital for further exploration and development of energy resources.
In addition to the above knowledge of subsurface formations will be improved. Downhole measurements while drilling will allow more accurate selection of zones for coring, and pertinent information on formations will be obtained while the formation is freshly penetrated and least affected by mud filtrate. Furthermore, decisions regarding completing and testing a well can be made sooner and more competently.
In order to accomplish the foregoing objectives of making downhole measurements and transmitting the information to the surface, it is necessary to insert and suspend a telemetering tool comprising a relatively long tubular casing concentrically within a drill collar. Electronic packages within the tubular telemetering tool such as converters, micro-processors, modulators, power amplifiers, etc. are mounted on generally square or rectangular printed circuit boards. These boards must then be securely suspended within the interior of the tubular tool and thus isolated from drilling mud within the drill collar.
In the past securing of square or rectangular objects in a tubular package was typically accomplished by drilling holes in the object and securing it with screws to a piece of material the size of the object. This secondary piece then fit inside the tubular package. This technique was quite costly and time consuming, and it had a tendency to translate outside shock and vibration directly to the object inside the tubular package. It will be appreciated by those skilled in the art that a drill collar of an operating rig is subject to considerable vibration and shock forces as the drill string penetrates through the earth.
Another technique utilized was to cut grooves inside the tubular package. The grooves were designed to have a width and length compatible with the object to be packaged and served to suspend the object. This required precision cutting inside a tubular member which, in the case of a telemetry tool, may be only an inch or so in diameter. Because of such size constraints, this technique was only feasible for axially short objects. Additionally, suspension systems using this technique were often structurally suspect.
The electronic components within a telemetering tool generate a degree of heat, often in concentrated zones. It would be highly desirable to be able to dissipate such heat concentrations within an electronic package of a telemetering tool.
The difficulties suggested in the preceding are not intended to be exhaustive, but rather are among many which may tend to reduce the effectiveness of prior heat sink/retainer members. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that heat sink/retainer members appearing in the past will admit to worthwhile improvement.